Low melting mesophase pitches

Abstract

A low melting point, low molecular weight, heptane insoluble, 1,2,4-trichlorobenzene soluble mesophase pitch useful in carbon fiber spinning as such or as a plasticizer in a carbon fiber spinning composition is obtained by heating chrysene, triphenylene or paraterphenyl as well as mixtures thereof and hydrocarbon fractions containing the same, dissolving the resulting heat treated material with 1,2,4-trichlorobenzene, and separating the insolubles, and then contacting the 1,2,4-trichlorobenzene soluble fraction with a sufficient amount of heptane to precipitate the low melting point, low molecular weight mesophase pitch.

What is claimed is: 
     
       1. A low melting, low molecular weight, heptane insoluble, 1,2,4-trichlorobenzene soluble mesophase pitch having a melting point of less than about 250° C. and a molecular weight of less than about 1000 prepared by the method which comprises heating a feed material selected from the group consisting of chrysene, triphenylene, and para-terphenyl, dissolving the heated material with 1,2,4-trichlorobenzene and recovering the soluble portion therefrom contacting the resulting 1,2,4-trichlorobenzene solution with heptane to precipitate said heptane insoluble, 1,2,4-trichlorobenzene soluble mesophase pitch. 
     
     
       2. The pitch of claim 1 also characterized by a C/H ratio of about 1.5 to 1.7. 
     
     
       3. A method of making a low melting, low molecular weight, heptane insoluble, 1,2,4-trichlorobenzene soluble mesophase pitch which comprises heating a feed material selected from the group consisting of chrysene, triphenylene, and para-terphenyl, dissolving the heated material with 1,2,4-trichlorobenzene and recovering the soluble portion therefrom contacting the resulting 1,2,4-trichlorobenzene solution with heptane to precipitate said heptane insoluble, 1,2,4-trichlorobenzene soluble mesophase pitch. 
     
     
       4. The method of claim 3 wherein said feed material is chrysene. 
     
     
       5. The method of claim 3 wherein said feed material is triphenylene. 
     
     
       6. The method of claim 3 wherein said feed material is paraterphenyl. 
     
     
       7. The method of claim 3 wherein said heating is effected by heat soaking at a temperature above about 300° C.